# CVE-2023-46838: Linux: netback processing of zero-length transmit fragment

> A NULL pointer dereference in the Linux kernel's Xen netback driver allows attackers to cause a denial of service via zero-length transmit fragments.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 29 Jan 2024
- **Updated:** 4 Nov 2025
- **Also known as:** ALPINE-CVE-2023-46838, AZL-34016, AZL-34863, BELL-CVE-2023-46838, DEBIAN-CVE-2023-46838, GHSA-m3mr-pjj3-2g74, UBUNTU-CVE-2023-46838

## What is CVE-2023-46838?

CVE-2023-46838 is a high-severity vulnerability in Debian Debian Linux, published on 29 Jan 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Transmit requests in Xen's virtual network protocol can consist of
multiple parts.  While not really useful, except for the initial part
any of them may be of zero length, i.e. carry no data at all.  Besides a
certain initial portion of the to be transferred data, these parts are
directly translated into what Linux calls SKB fragments.  Such converted
request parts can, when for a particular SKB they are all of length
zero, lead to a de-reference of NULL in core networking code.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2023-46838?

It affects 3 products.


Products: Debian Debian Linux, Fedoraproject Fedora, Linux kernel.

## How do I fix CVE-2023-46838?

Apply the vendor's patch.

## Is CVE-2023-46838 being exploited?

There is no known exploitation of CVE-2023-46838 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-46838 and fix it if it is affected.

What it is: CVE-2023-46838 is a high-severity vulnerability in Debian Debian Linux, published on 29 Jan 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-46838 in the wild and no public exploit code.

Affected product: Debian Debian Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-46838/ (Markdown: https://insights.sbomify.com/CVE-2023-46838/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-46838
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-46838
- OSV: https://osv.dev/vulnerability/CVE-2023-46838

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-46838/
Summaries are generated and may contain mistakes; the official description above is the record.